Energy Notes (cont.)

Energy Conversion and Conservation

LAW OF CONSERVATION OF ENERGY - when one form of energy is converted to another, no energy is destroyed. Energy cannot be created or destroyed.

**In every physical change or chemical change, the total amount of energy stays the same.

Friction: The transformation of kinetic energy to heat energy that occurs when two objects rub together. Ex. Rubbing your hands together to

warm them up (mechanical energy to thermal energy.

Energy Conversions – the energy you use to toast your bread may have had a very long history…1. The sun converts nuclear energy to electromagnetic energy (radiant energy).2. Ancient plants and animals convert electromagnetic energy from the sun to stored chemical energy.3. Remains of plants and animals become coal over millions of years.4. Stored chemical energy in coal is converted to thermal energy when coal is burned to make steam.5. Thermal energy is converted to mechanical energy as turbines are turned by steam.6. Mechanical energy is converted to electrical energy as turbines turn electric generators.7. Electrical energy is converted to thermal energy in your toaster.

Gravitational Potential Energy

Potential energy that is dependent on height is called gravitational potential energy.

Gravitational Potential Energy

A waterfall, a suspension bridge, and a falling snowflake all have gravitational potential energy.

Gravitational Potential Energy

• “The bigger they are the harder they fall” is not just a saying. It’s true. Objects with more mass have greater G.P.E.

• The formula to find G.P.E. isG.P.E. = Weight X Height.

Temperature and Thermal Energy

TEMPERATURE - a measure of the average kinetic energy of the individual particles in an object. Thermal Energy – is the total energy of all of the particles.

HEAT - The movement of THERMAL ENERGY from a substance at a higher temperature to another at a lower temperature

CALORIE - a unit of heat energy - the amount of heat required to raise the temperature of 1 g of pure water by 1º Celsius

**Heat can move in 3 different ways

CONDUCTION - heat is transferred from one particle of matter to another WITHOUT the movement of matter itself.

CONVECTION - heat is transferred by the MOVEMENT of currents within a fluid (a liquid or a gas).

RADIATION - the transfer of energy by electromagnetic waves. Radiation does NOT require matter to transfer thermal energy.

**A material that conducts heat well is called a conductor.

**A material that does NOT conduct heat well is called a insulator.

Activity

• 1. My energetic morning• 2. Energy Forms and Conversions